I did some serious reading about the craft of writing a few years ago. I was torn about the desire to write a book versus my time spent mothering and homeschooling and seriously considered making time, finding more time for writing with an aim for publication. I have since decided it's not the right time in my life for such a project. I have other higher priorities at the moment and am unwilling to take extra steps to make it happen (such as live on less sleep than my body requires for good health in order to write late at night or before dawn).
Anyhow one thing I read over and over was really you need BIC or Butt in Chair time. You just can't get the writing done if your butt is not in the chair and you are not writing. When you think about it it seems like a no-brainer but honestly some people expect results without putting in the work to get the results, or they think about doing something a lot, instead of putting that time to doing the thing, (such as me with my dream of having a book published). One author said something to the effect of "some people want to have had a book published not to actually do the work to write the book that is worthy of being published". That was an epiphany for me.
I'm sharing this today as the same is true for homeschooling regarding BIC.
If you choose to teach a subject at home you must do more than research and buy the curriculum you have to use it.
Sometimes a curriculum gets blamed for not being good enough when the actual problem is that it was never used. The homeschooling mother must use self-discipline to administer the lessons. The kids must put forth the effort to do the work, including studying and using extra effort if the learning is not happening magically and instantly.
Sometimes a curriculum and the plans are sound, and really it requires plugging away and away and away then the next thing you know the content is being mastered and the learning gets easier. At some point the curriculum is finished and we can rejoice by saying "he finished grade five math"!
(I'll not go into a rant as some unschoolers do about who defines what is fifth grade math and that learning stuff in life never ends. Instead I will bask in the warm fuzzy feeling that happens when something is finished up and it can be said that "he finished"!)
Sometimes curriculum is clearly is a bad fit and other options or different teaching methods must be used.
Mostly though, good things will come to those students who plug away, plug away, and plug away. Put the butt in the chair, do the work, and the learning will happen. Trust me.
Also in some situations the student suddenly finds they cannot master or memorize content unless they study. Thus the homeschooled student who formerly just did a little work on something and mastered it must actually have to apply themselves and do studying such as the way we parents recall having to do it in school or college. That is an indication their studies have moved up to the next level.
If after considerable effort and creative learning techniques, a child cannot learn or master a concept, consider having your child tested for learning disabilities. With good teaching and good materials and sometimes also some creative effort, learning does happen, if it is not happening after much effort on both the mother and child's part, honestly the child may have some problem that needs addressing with special therapies. If your child is bright but really struggles to learn certain things that may be a red flag that something else is going on that needs special attention.
Update: In case it wasn't clear, I'll share a bit more. I'm happy lately about putting time in for learning and seeing results. I know others can achieve results by the same method if the effort was put forth. I know from experience that sometimes the curriculum really is not a good fit or just seems to stink, but other times it's the teacher to blame (I mean in my case, I was to blame).
Regarding the learning disabilies I know from experience that no matter how hard a student tries sometimes it will never be enough: a formal diagnosis is needed to help guide an uninformed parent to receive therapies or learn new teaching methods or different study methods for the student to use.
This is about putting forth effort toward a desired goal. Playing the blame game and not doing the work and complaining about not reaching the goal is a waste of time. If anyone really wants to achieve a desired result then right action with good intention must happen. A good work ethic and perseverance makes it do-able.